Because they’re so fuel-efficient, used Prius hybrids don’t come cheap, and some road-warrior commuters rack up lots of miles in them. Toyota warrants the battery pack for 8 yrs/100,000 miles or 10 yrs/150,000 miles (depending what state you’re in), so newer Priuses may be safer bet if you worry about battery life—which has been very good on average. Most used Priuses now are the 2004-2009 model; earlier 2001-2003 models are considerably slower.